Class Materials for CHEM 21A at El Camino Community College

The following documents are for Chapter 2 that was used in this class. Please download them and bring them to class.



  • Chapter 2 - Section 2.1 - Symbols and Formulas
  • Chapter 2 - Section 2.2 - Inside the Atom
  • Chapter 2 - Sections 2.3, 2.4,and 2.5 - Atomic Number and Mass Number
  • Chapter 2 - Sections 2.3, 2.4,and 2.5 - Isotopes and Atomic Weights
  • Chapter 2 - Section 2.6 and 2.7 - The Mole and Chemical Formulas